BLyS up-regulation correlates with CD86 expression in maturing DCs exposed to a variety of antigenic stimuli or in B-cell cocultures. FACS-sorted splenic CD11c⁺ cells were cultured under different conditions to define a correlation between BLyS up-regulation and CD86 expression after exposure to a variety of antigenic stimuli or B-DC cocultures. Open bold histograms show the expression of BLyS in CD86⁺ gated cells compared with isotype controls (solid histograms). The culture conditions tested were: (A) GM-CSF alone; (B) 2.5 μg/mL LPS; (C) 5 × 10⁶ necrotic EL-4 cells; (D) 5 × 10⁶ apoptotic EL-4 cells; and (E) 5 × 10⁶ splenic B cells.